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Ask Well: Do Cranberries Offer Health Benefits?

Q

Does cranberry juice have health benefits?

Reader Question • 608 votes

A

Cranberry juice is a popular folk remedy for staving off urinary tract infections and the berries contain chemical compounds with potentially powerful antibacterial properties. But clinical trials that have tested cranberry products have yielded mixed results, possibly because studies tested juices and supplements with varying amounts of active ingredients. Many trials also had high dropout rates.

The most recent Cochrane review on cranberries, from 2012, analyzed two dozen trials involving 4,473 participants and concluded that cranberries are no more effective for preventing U.T.I.s than placebos. But the review also suggested that cranberry products may reduce symptomatic infections among women with recurrent U.T.I.s.

Dr. William E. Cayley, a family medicine professor at the University of Wisconsin who wrote a synopsis of the Cochrane evidence in American Family Physician, said cranberry products should not be recommended to prevent U.T.I.s, but, “If someone says they want to try drinking it, I’m not going to tell them, ‘Don’t do it.’”

Cranberries contain chemical compounds called proanthocyanidins that can prevent E. coli bacteria from sticking to the bladder walls, “preventing the first step in the infection process,” said Amy Howell, an associate research scientist at the Marucci Center for Blueberry and Cranberry Research and Extension at Rutgers University. Dr. Howell explained that if bacteria cannot stick to a cell, they cannot multiply and produce toxins.

Most cranberry juices you will find in grocery stores contain added sweeteners or are mixed with sweeter juices. To get enough of the active cranberry ingredients, choose a drink with at least 25 percent pure cranberry juice, Dr. Howell said, and drink eight to 10 ounces a day.